1. Molecular Therapy - Nucleic Acids
Therapeutic Silencing of Bcl-2 by Systemically Administered siRNA Nanotherapeutics Inhibits Tumor Growth by Autophagy and Apoptosis and Enhances the Efficacy of Chemotherapy in Orthotopic Xenograft Models of ER (−) and ER (+) Breast Cancer 
Ibrahim Tekedereli, S Neslihan Alpay, Ugur Akar, Erkan Yuca, Cristian Ayugo-Rodriguez, He-Dong Han, Anil K Sood, Gabriel Lopez- Berestein, Bulent Ozpolat 
Molecular Therapy - Nucleic Acids 
Volume 2, (January 2013)
DOI: /mtna
Copyright © 2013 American Society of Gene & Cell Therapy Terms and Conditions

2. Figure 1
Silencing of Bcl-2 by a specific siRNA inhibits proliferation and colony formation of ER(−) breast cancer cells. (a) MDA-MB-231 cells were treated with control or Bcl-2 siRNA for 48 hours and analyzed using anti-Bcl-2 monoclonal antibody by western blot analysis. (b) Silencing of Bcl-2 by siRNA inhibits size and number of colonies formed by MDA-MB-231 cells. Cells were treated with Bcl-2 or control siRNA once a week and colonies were detected 2 weeks later. Bcl-2 silencing significantly reduced colony size and area (88%, P < ) (c) and the colony number (69%, P < 0.006) (d) of MDA-MB-231 colonies as compared with nonsilencing control siRNA-treated cells (*P < 0.05). (e) Morphological appearance of breast cancer cells treated with Bcl-2 siRNA by phase contrast microscopy (72 hour-MCF7) at 10 and 40× magnification.
Molecular Therapy - Nucleic Acids 2013 2, DOI: ( /mtna )
Copyright © 2013 American Society of Gene & Cell Therapy Terms and Conditions

3. Figure 2
Time- and dose-dependent kinetics of Bcl-2 inhibition by systemically administered nanoliposomal (NL)-Bcl-2-siRNA in MDA-MB-231 orthotopic xenograft model. (a) Mice-bearing MDA-MB-231 tumors were injected with a single i.v. dose of NL-Control-siRNA or NL-Bcl-2-siRNA (0.075 or 0.15 mg siRNA/kg from tail vein) and tumors were removed on days 2, 4 and 6. Inhibition of Bcl-2 protein expression was detected by western blot analysis of tumor lysates. (b) Inhibition of Bcl-2 protein expression by densitometric analysis of bands shown in 1A tumors.
Molecular Therapy - Nucleic Acids 2013 2, DOI: ( /mtna )
Copyright © 2013 American Society of Gene & Cell Therapy Terms and Conditions

4. Figure 3
Therapeutic silencing of Bcl-2 by NL-Bcl-2 siRNA inhibits in vivo tumor growth of ER(−) MDA-MB-231 xeonografts in nude mice. (a) Mice were orthotopically injected into mammary fat pat with luciferase-expressing MDA-MB-231 cells. Mice-bearing tumors with equal size were randomly assigned into control and treatment groups (n = 5 mice per group). Mice received either NL-Bcl-2 siRNA or NL-control siRNA treatments (0.15 mg siRNA/kg or 4 µg/mouse, i.v, twice a week) from tail vein for 4 weeks (total of eight injections). After 4-weeks of treatments, mice were imaged following luciferin injection (i.p.) by Xenogen-IVIS live-imaging system under anesthesia. (b) Therapeutic silencing of Bcl-2 by NL-Bcl-2 siRNA enhances the antitumor efficacy of doxorubicin. Mice were treated with NL-Bcl-2-siRNA or NL-control siRNA (0.15 mg siRNA/kg, i.v, twice a week) and also received doxorubicin (4 mg/kg, i.p, once a week) for 4 weeks and imaged. (c) Mice that were treated with NL-Bcl-2 siRNA had significantly reduced tumor weight compared with the control group that was treated with NL-Control siRNA. Enhanced the antitumor efficacy of doxorubicin was observed when combined with NL-Bcl-2 siRNA. The tumor weights were measured 4 weeks of treatments shown in Figure 3a, b. (d) Bcl-2 protein expression after 4 weeks of treatments in MDA-MB-231 tumors. After sacrificing mice, tumors were removed (48 hours after the last treatment) and tumor lysates were analyzed for Bcl-2 expression by western blot. (e) NL-Bcl-2-siRNA treatment was well tolerated and did not cause weight lose in mice, compared with those that received NL-control siRNA. Mice that received doxorubicin had slight reduced weight loss compared with those that did not receive chemotherapy. (f) In vitro silencing of Bcl-2 by siRNA treatment increases the antiproliferative effects of paclitaxel and inhibit colony formation of MDA-MB-231 cells.
Molecular Therapy - Nucleic Acids 2013 2, DOI: ( /mtna )
Copyright © 2013 American Society of Gene & Cell Therapy Terms and Conditions

5. Figure 4
In vivo therapeutic targeting of Bcl-2 by nanoliposomal siRNA inhibits growth of ER(+) MCF-7 tumors and increases the activity of chemotherapy in an orthotopic xenograft model in mice. (a) About 2 weeks after tumor cell injection, mice-bearing equal size of MCF-7 tumors were randomly assigned to groups (n = 6) and treated with either NL-Bcl-2-siRNA or NL-control siRNA alone (0.15 mg siRNA/kg, i.v, twice a week) or in combination with doxorubicin (3 mg/kg, i.p, once a week) for 4 weeks. Mice treated with NL-Bcl-2 siRNA alone and NL-Bcl-2 siRNA and doxorubicin had significantly smaller tumor xenografts when compared with the control group (P = and P = 0.006, respectively) (*P < 0.05). The representative tumors from each treatment group is shown below the chart. (b) Mice treated with NL-Bcl-2 siRNA (4 weeks) showed marked inhibition of Bcl-2 protein in MCF-7 tumors. Tumors were collected at the end of 4 weeks of treatment (a) and analyzed by western blot.
Molecular Therapy - Nucleic Acids 2013 2, DOI: ( /mtna )
Copyright © 2013 American Society of Gene & Cell Therapy Terms and Conditions

6. Figure 5
In vivo silencing of Bcl-2 induces autophagy and apoptosis in ER(−) MDA-MB-231 tumors. (a) After 4 weeks treatment with NL-control siRNA or NL-Bcl-2 siRNA treatments, MDA-MB-231 tumors shown in Figure 3a were analyzed by western blot for detection activated/cleaved caspase-9 and PARP for evaluation of apopotosis. (b) Autophagy induction in MDA-MB-231 tumors was evidenced by detection of autophagy marker LC3-II in. (c) NL-Bcl-2-siRNA treatment-induced apoptosis was also shown by TUNEL staining of MDA-MB-231 tumors. (d) Quantification of TUNEL-positive cells in (c) shows that inhibition of Bcl-2 led to a threefold increase in apoptotic cells (P < 0.05). (e) Silencing of Bcl-2 expression by NL-Bcl-2-siRNA induced apoptosis and autophagy in MCF7 tumors. MCF tumors shown in Figure 4a were analyzed by western blot using specific antibodies to cleaved/activated caspase-9 for detection of apoptosis and LC3-II and ATG5 for detection of autophagy as described in the “Materials and Methods.” (f) NL-Bcl-2-siRNA treatment inhibited Ki-67 proliferation marker expression as indicated by immunohistochemistry (IHC). Ki-67 positive cells stained by IHC were quantified by counting five field from each tumor, indicating significant reduction of Ki-67 expression (*P < 0.05).
Molecular Therapy - Nucleic Acids 2013 2, DOI: ( /mtna )
Copyright © 2013 American Society of Gene & Cell Therapy Terms and Conditions

7. Figure 6
Autophagy contributes to cell death induced by Bcl-2 silencing in breast cancer cells. (a) Inhibition of autophagy by knocking down autophagy genes, including Beclin-1 or ATG8 inhibits cell death induced by Bcl-2-siRNA in MDA-MB-231 cells. Bcl-2 siRNA treatment was started 48 hours after control, Beclin1 or ATG8 siRNA transfections in MDA-MB-231 cells and cell death was assessed about 48 hours after Bcl-2 siRNA treatment. (b) Doxorubicin-induced autophagy is mediated by Bcl-2 downregulation in MDA-MB231 breast cancer cells. Doxorubicin treatment leads to Bcl-2 downregulation, which leads to autophagy induction as evidenced by increased expression of LC3-II autophagy marker. (c) Silencing of Bcl-2 by siRNA increased doxorubicin-induced autophagy in MDA-MB-231 cells. Cells were treated Bcl-2 siRNA for 24 hours and later incubated with doxorubicin for 48 hours. Western blot analysis shows that combination therapy (Bcl-2 siRNA and doxorubicin) induces more potent authophagy as evidenced by LC3-II and ATG5 expression. (d) Silencing of Bcl-2 by siRNA leads to autophagy as indicated by upregulation of Beclin-1 autophagy promoting protein in MDA-MB-231 cells. (e) Silencing of Bcl-2 by siRNA also induces autophagy MCF7/DoxR breast cancer cells as evidenced by LC3-II induction and apoptosis.
Molecular Therapy - Nucleic Acids 2013 2, DOI: ( /mtna )
Copyright © 2013 American Society of Gene & Cell Therapy Terms and Conditions

8. Figure 7
In vivo therapeutic silencing of Bcl-2 by nanoliposomal siRNA treatment inhibits activation of focal adhesion kinase (p-FAK), cyclin D1, HIF1α in tumors. Tumors shown in Figure 4a were analyzed after 4 weeks of treatments with NL-Bcl-2-siRNA or NL-control siRNA alone (0.15 mg siRNA/kg, i.v, twice a week). Mice treated with NL-Bcl-2 siRNA had reduced activity of Src and FAK signaling pathways and expression of Cyclin D1 and HIF1α in tumor xenografts when compared with corresponding control groups for 4 weeks of treatment.
Molecular Therapy - Nucleic Acids 2013 2, DOI: ( /mtna )
Copyright © 2013 American Society of Gene & Cell Therapy Terms and Conditions

9. Figure 8
Proposed mechanism of Bcl-2 silencing and doxorubicin-induced events in breast cancer cells. Bcl-2 silencing by specific siRNA and doxorubicin induce apoptosis and autophagy that is mediated by downregulation Bcl-2 and induction of ATG5 and Beclin1. Inhibition of autophagy genes prevents cell death by Bcl-2 silencing suggest that autophagy contributes to cell death in MDA-MB-231 breast cancer cells.
Molecular Therapy - Nucleic Acids 2013 2, DOI: ( /mtna )
Copyright © 2013 American Society of Gene & Cell Therapy Terms and Conditions